1. Field of the Invention
The present invention relates to a method of manufacturing an electrode for a battery, and more particularly, to a method of manufacturing an electrode for a secondary battery, which enables cost savings and the manufacture of products having various sizes and shapes.
2. Description of the Related Art
Generally, a chemical battery refers to a battery composed of a positive electrode, a negative electrode, and an electrolyte to thus generate electrical energy using a chemical reaction, and is classified into a primary battery, which is disposable, and a secondary battery, which is chargeable and dischargeable, thus enabling repeated use. The use of such a secondary battery is gradually increasing due to the advantage of its chargeable and dischargeable characteristic.
Among secondary batteries, a lithium secondary battery has high energy density per unit weight, and thus is widely used as a power source in electronic communication devices and in high-power hybrid vehicles.
The lithium secondary battery includes an electrode group, composed of a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes, and a positive electrode tab and a negative electrode tab respectively connected to the positive electrode and the negative electrode. In general, the electrodes such as the positive and negative electrodes are manufactured in such a way that an electrode plate is shaped into a predetermined electrode pattern using a metal die.
When the electrodes are manufactured using a metal die, each of the electrodes defined in the electrode plate must be provided on four sides thereof with tolerances corresponding to more than 10% of the thickness of the electrode plate. In order to ensure providing such a tolerance, a portion of the electrode plate must be disposed of, thus causing the loss of raw material. Consequently, the cost of manufacturing electrodes may be increased and the productivity of electrodes may be greatly reduced.
In this regard, after the electrodes are manufactured using a metal die, debris adhering to the metal die may fall on the electrode plate, and thus micro short-circuits may occur. This may cause the deterioration of reliability of a battery equipped with the electrodes. In order to avoid such defects, the electrode must have an additional resin layer or film and the like disposed thereunder, and thus manufacture of such electrodes is problematic.
In addition, since the metal die has a fixed size and shape, it is possible to manufacture only one type of electrode having fixed size and shape using one metal die. Accordingly, when the size and shape of an electrode must be changed even slightly according to variation in the requirements of customers or market circumstances, all of the equipment for manufacturing the electrode must be replaced.